Load balancing for single-address tenants

• US 9,092,271 B2
• Filed: 08/05/2014
• Issued: 07/28/2015
• Est. Priority Date: 07/12/2012
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Murthy, Ashwin, Patel, Parveen Kumar, Bansal, Deepak, Zikos, Marios
• Primary Examiner(s): KATSIKIS, KOSTAS J
• Application Number:
  US14/452,314
• Publication Number:
  US 20140351395A1
• Time in Patent Office: 357 Days
• Field of Search: 709/222, 709/223, 709/238
• US Class Current: 1/1
• CPC Class Codes: G06F 15/173 using an interconnection network, e.g. matrix, shuffle, pyramid, star, snowflake
• CPC Class Codes: G06F 9/5083 Techniques for rebalancing the load in a distributed system
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/38 Flow based routing
• CPC Class Codes: H04L 45/72 Routing based on the source address
• CPC Class Codes: H04L 45/76 Routing in software-defined topologies, e.g. routing between virtual machines
• CPC Class Codes: H04L 67/10 in which an application is distributed across nodes in the network software deployment G06F8/60; multiprogramming arrangements G06F9/46
• CPC Class Codes: H04L 67/1027 Persistence of sessions during load balancing
• CPC Class Codes: H04L 67/34 involving the movement of software or configuration parameters network booting or remote initial program loading [RIPL] G06F9/4416

Abstract

When a load balancer detects that a virtual address is associated with a single destination address, the load balancer sets a flag to distinguish the virtual address from virtual addresses that are associated with a plurality of destination addresses. The load balancer instructs the router to bypass the load balancer for network packets that are addressed to the virtual address, and refrains from storing subsequent flow state for the virtual address. When the virtual address is to be scaled up with an additional destination address, the load balancer sets a flag to distinguish the virtual address from virtual addresses that are associated with a single destination addresses. The load balancer instructs the router to route network packets that are addressed to the virtual address through the load balancer, instead of bypassing the load balancer, and starts storing flow state for the virtual address.

Claims

1. A computer system configured as a load balancer that controls the routing of network packets between virtual addresses and destination addresses, the computer system comprising:

one or more processors; and

one or more computer storage device having stored computer-executable instructions which, when executed by the one or more processors, implement a method for managing flow state of a virtual address, the method comprising;

an act of the load balancer detecting that a virtual address that is being managed by the load balancer is to be scaled up from being associated with only a first destination address to being associated with at least an additional second destination address;

in response to detecting, an act of the load balancer sending a configuration message to a router, the configuration message interpretable by the router as an instruction to send network packets that are addressed to the virtual address to the load balancer, and cease a previous practice to bypass the load balancer for network packets that are addressed to the virtual address; and

subsequent to sending the configuration message to the router, an act of the load balancer storing flow state for the virtual address.

2. The computer system of claim 1, wherein the load balancer storing flow state for the virtual address comprises the load balancer storing information that identifies the destination address corresponding to active flows.

3. The computer system of claim 1, wherein the method further includes the load balancer distinguishing the virtual address from other virtual addresses that are associated with a single destination address.

4. The computer system of claim 3, wherein the distinguishing is performed by setting a flag for the virtual address.

5. The computer system of claim 1, wherein one or both of the first destination address or the second destination address is associated with a corresponding server.

6. The computer system of claim 5, wherein the corresponding server for one or both of the first destination address or the second destination address comprises a virtual machine.

7. The computer system of claim 5, wherein the corresponding server for one or both of the first destination address or the second destination address comprises physical hardware.

8. The computer system of claim 5, further comprising an act of the load balancer probing one or both of the first destination address or the second destination address to ascertain health of the corresponding server.

9. The computer system of claim 8, wherein the act of probing one or both of the first destination address or the second destination address comprises one or more of:

establishing a network connection with the corresponding server,

sending a ping message to the corresponding server, or

fetching a Hypertext Transfer Protocol (HTTP) Uniform Resource Locator (URL) at the corresponding server.

10. The computer system of claim 8, wherein when the probing indicates that a particular corresponding server is not responding, the load balancer ceases sending network traffic to a destination address associated with the particular corresponding server.

11. A computer program product comprising computer memory containing computer-executable instructions which, when executed by one or more processors, cause the one or more processors to perform a computer-implemented method for configuring load balancing for a virtual address, and wherein the computer-implemented method comprises:

an act of the load balancer detecting that a virtual address that is being managed by the load balancer is to be scaled up from being associated with only a first destination address to being associated with at least an additional second destination address;

in response to detecting, an act of the load balancer sending a configuration message to a router, the configuration message interpretable by the router as an instruction to send network packets that are addressed to the virtual address to the load balancer, and cease a previous practice to bypass the load balancer for network packets that are addressed to the virtual address; and

subsequent to sending the configuration message to the router, an act of the load balancer storing flow state for the virtual address.

12. A computer-implemented method for configuring load balancing for a virtual address, the computer-implemented method being performed by one or more processors when executing computer-executable instruction for the method, and wherein the computer-implemented method comprises:

an act of the load balancer detecting that a virtual address that is being managed by the load balancer is to be scaled up from being associated with only a first destination address to being associated with at least an additional second destination address;

in response to detecting, an act of the load balancer sending a configuration message to a router, the configuration message interpretable by the router as an instruction to send network packets that are addressed to the virtual address to the load balancer, and cease a previous practice to bypass the load balancer for network packets that are addressed to the virtual address; and

subsequent to sending the configuration message to the router, an act of the load balancer storing flow state for the virtual address.

13. The computer-implemented method of claim 12, wherein the method further includes the load balancer distinguishing the virtual address from other virtual addresses that are associated with a single destination address.

14. The computer-implemented method of claim 13, wherein the distinguishing is performed by setting a flag for the virtual address.

15. The computer-implemented method of claim 12, wherein one or both of the first destination address or the second destination address is associated with a corresponding server.

16. The computer-implemented method of claim 15, wherein the corresponding server for one or both of the first destination address or the second destination address comprises a virtual machine.

17. The computer-implemented method of claim 15, wherein the corresponding server for one or both of the first destination address or the second destination address comprises physical hardware.

18. The computer-implemented method of claim 15, further comprising an act of the load balancer probing one or both of the first destination address or the second destination address to ascertain health of the corresponding server.

19. The computer-implemented method of claim 18, wherein the act of probing one or both of the first destination address or the second destination address comprises one or more of:

establishing a network connection with the corresponding server,

sending a ping message to the corresponding server, or

fetching a Hypertext Transfer Protocol (HTTP) Uniform Resource Locator (URL) at the corresponding server.

20. The computer-implemented method of claim 18, wherein when the probing indicates that a particular corresponding server is not responding, the load balancer ceases sending network traffic to a destination address associated with the particular corresponding server.

21. The computer-implemented method of claim 12, wherein the load balancer storing flow state for the virtual address comprises the load balancer storing information that identifies the destination address corresponding to active flows.